1. Field of the Invention
The present invention relates to virtual reality (VR) and, more particularly head-mounted displays (HMD), to one or arrangement may provide a "stereo" view simulating actual vision. A preferred embodiment of the present invention uses an electronic panning camera, and multiple users may be connected to a single camera and each user may individually control the portion of the scene that the user views without affecting the view of other users.
2. Discussion of Related Art
Researchers in video communications technologies continue to seek ways to provide a person with a greater sense of "being there" via networked communications. Two well known examples of providing this sense are (1) teleconferencing--which provides face-to-face communications between persons at remote locations--and (2) virtual reality--which provides a person with the feeling of actually being at a particular (real or imaginary) location using computer generated simulations.
Technologies aimed at providing network subscribers a high degree of "telepresence"; that is, being able to observe and interact at a remote site, as though physically there, have been pioneered by the assignee of the present invention. For example, the assignee developed the electronic panning camera (described in U.S. Pat. Nos. 5,187,571 and 5,532,737), which provides users with the ability independently (and without affecting the view of other users of the same camera) to pan, zoom, and tilt video images of a remote site gathered by a non-moving camera, and display the images on standard monitors with complete view control.
It is desirable to develop new technologies which allow end-users to immerse themselves in a remote site and look around as though physically there. This may be done by combining the broad look-around capabilities of the electronic panning camera with head-mounted display (HMD) technology, such as is currently used in virtual reality (VR) applications. This combination may allow a user to look around at a remote site over a wide angle simply by moving his/her head.
Prior known VR systems have certain limitations. FIG. 1 illustrates a conventional virtual reality system 100. Here, a user 102 wears a head-mounted display 104 having a head position tracking device 106. The tracking device and HMD are connected to a VR rendering engine 108.
An HMD 104 typically comprises two small video displays (one for each eye) and an optical system which allows the eyes to focus on the screens at close range (typically an inch or so). Because the lens system produces a carefully placed virtual image for each eye, the user appears to see a large image, several feet in front of the user which subtends a fairly large portion of the user's visual field. Typical HMDs 104 provide a field of view between 30.degree. to 60.degree. or more.
Coupled with the HMD 104 is the head-tracking system 106, which reports the head position (and thus the gaze direction) of the user to the VR rendering engine 108. The head position data is delivered to the rendering engine 108 (which may be a high-speed graphics computer) which contains an image data-base. The head position of the user corresponds to the portion of the image the user wishes to see. Thus, the desired portion of a computer-generated scene is determined by the head-tracker device output and the appropriate portion of the scene is rapidly called up from the rendering engine's 108 database. This portion of the scene is displayed for each of the user's eyes. Thus, if the user looks to the left or right, the appropriate image is presented on the displays. The overall effect is that of being located in a surrealistic computer generated environment with the ability to freely look around. As an enhancement to the psychological impact of the effect, the views delivered to each eye are often generated as stereo-pairs having the proper binocular disparity to allow the viewer to see depth in the imagery. Note that images portrayed in a VR system are not real-time video images of real world objects, but rather are computer generated approximations of real or fanciful scenes.
Similar techniques, such as full look-around telepresence, have also been used for controlling remote vehicles, or operating machinery in dangerous or inaccessible locations such as in mines or in outer-space. FIG. 2 illustrates a set-up 200 for such a technique. As seen in FIG. 2, a user 202 wears an HMD 204 with a head tracking system 206. The HMD and head-tracking system are connected to a camera 208 on a panning and tilting stand 210.
In FIG. 2, the user's 202 gaze direction is determined by the head-tracking system 206 and transmitted to a remote location. A television or video camera 208 mounted on a remotely controllable panning and tilting stand 210 moves in a manner synchronized to the user's gaze direction, and transmits images back to the user 202. Stereo viewing may be provided by using two separate cameras 208, 208' (one for each eye view), each connected to a panning and tilting stand 210, 210'.
The effect can be powerful, but is limited in several respects. One important limitation, particularly from a video communications or teleconferencing network provider's perspective, is that the remotely operated camera is a single-user system. That is, only a single user can control the panning and tilting of the camera and look through the viewing system.
Therefore, it is an object of the present invention to provide an apparatus and method for providing a system connecting displays, such as head-mounted displays, to a networked panning camera to permit multiple users to view the same remote scene.
It is yet another object of the present invention to provide an apparatus and method for connecting displays, such as head-mounted displays, to an electronic panning camera to permit multiple users to independently view different views of the same remote scene without interfering with any other viewer's image.
It is an even further object of the present invention to provide an apparatus and method for providing a "stereo" view of a scene being viewed for a depth-of-field effect simulating actual vision.